Facile synthesis of (polyfluoro)alkanesulfinyl 4-isoxazolines: a stepwise solvent- and catalyst-free approach or a one-pot process in water

4-Isoxazolines are important motifs in various biologically interesting molecules and versatile synthons for the preparation of various cyclic and acyclic compounds. Herein, two green and facile protocols were reported for the synthesis of a wide range of polyfluoroalkanesulfinyl or alkylsulfinyl 4-isoxazolines. A variety of aldehyde and ketone derived nitrones reacted with alpha-alkynyl sulfoxides under catalyst- and solvent-free conditions at room temperature to provide a series of polyfluoroalkanesulfinyl or alkylsulfinyl 4-isoxazolines with high efficiency. The synthesis of these sulfinyl 4-isoxazolines was further improved to a one-pot process in aqueous medium starting from aldehydes and hydroxylamine hydrochlorides without the need for isolating the nitrones. The reactions developed in this work are easy to perform and demonstrate significant ecological advantages.